I managed to wave 29. Arrgh! Rage quit!
Visually it's beautiful. I liked all gameplay elements and I really wanted to unconditionally love this game. But something won't let me. Every gameplay aspect is good but it also comes with a minuscule annoyance of one kind or another. When all those itsy bitsy annoyances add up, it leaves you with feeling of frustration. As a bubble, I never felt powerful. Maybe that was the point. I'll still give the game high grades though. There's a great game in there that wants to be freed. And you're very very close to doing so.
Let me try to address some of it, in no particular order. Well, the first thing may be the most important.
It's too bouncy. Everything is so bouncy. I know it's bubbles, but it's too bouncy. Whatever you touch, you bounce, often times the bounce speed is insanely high. Coupled with very strong controls inertia, it sends you into a cascade of uncontrollable bounces that end up with inevitable death. Things that deliver damage, punish you additionally by - bouncing you. The edge of the arena bounces you. The use of bounce needs to be more - measured. The only way to play in a more calm way is to get the heavy modifier. The default controls should be like for heavy. The feel of the game may still be very bouncy, but that doesn't mean that a literal bounce is scheduled to happen every half a second. Give it some solidity so the bounces may shine in contrast to it.
All enemies always fire at the same time. Not sure if this is good or bad.
There's no pronounced feedback when you get hit. Because of that I had hard time learning what is dangerous to touch. Often times I still don't know if I've been hit or not.
The enemy explosions should be audiovisually juicer. Let them pop with gusto. Maybe introduce some tiny, pixel sized "aerosol" particles. Make everything explode immediately without that pause. The enemy rebound strictly in the direction of shooting may be better than "realistic" circle-to-circle collision resolve (or dare I say it - bounce). It's perceptually too random and makes almost impossible to fire a satisfying burst into an enemy.
Some good remarks on visual design have already been given by others so I won't repeat them.
There's a dominant strategy I think and it's mostly focused on minimizing getting - bounced: Get heavy as soon as possible, just circle the edge of the arena and fire into the center. When all enemies are dead, clear the red things. Repeat until wave 30.
A few more enemy types would be cool.
So what to do? Gather a couple of sharp testers that are not afraid to say what they think, weed out all those micro annoyances and you'll have a golden game on your hands.